In this proposal, we are requesting support for the purchase of a mass spectrometer to perform experiments involving identification and quantification of protein expression levels and post-translational modifications (PTMs). Specifically, we are requesting a hybrid quadrupole time-of-flight mass spectrometer system (QSTAR XL) from Applied Biosystems. The abilities of this instrument to accurately measure both peptide masses and fragment ion masses as well as provide complementary MS/MS fragmentation patterns will offer increased certainty in the analysis of PTMs found in protein samples. In addition, the system has been engineered to facilitate not only the identification, but also the quantification of proteins within a given sample using novel iTRAQ reagents. As the field of proteomics moves beyond the level of simple identification into the more challenging realm of changes in protein structure and expression, it is vital that we acquire instrumentation which will allow our investigators to probe these effects. This instrument will be housed in the University of Virginia Biomolecular Research Facility and will support the research proteomics projects of eight NIH-funded investigators. For these projects, we anticipate that the instrument will be used approximately 80% of the available time. The remaining time will be made available for new proteomic project development. [unreadable] [unreadable] Dr. Jay Fox, Assistant Dean for Research, will be responsible for the overall management of the instrumentation. Dr. Nicholas Sherman will be responsible for interacting with investigators concerning the planning and execution of experiments and data interpretation. Dr. Kristina Nelson will be responsible for daily operation and maintenance of the instrument as well as data analysis. The Biomolecular Research Facility has been providing mass spectrometric expertise for the past 11 years, and we expect seamless integration of the requested system with current instrumentation. A fee-for-service charge will be instituted to help defray the costs of staff salaries and supplies. [unreadable] [unreadable] The oversight of the Biomolecular Research Facility is provided by a standing committee appointed by the Dean of the Medical School. The Oversight Committee provides guidance and expertise directly to Dr. Fox for the management of the facility as well as complementing the scientific expertise of facility staff. The University of Virginia Biomolecular Research Facility has been in operation for the past 24 years with continual fiscal support by the Health Sciences Center. The support by the administration, along with the operational plan, ensures adequate and appropriate instrument use for the fiscally sound and scientifically successful operation of instrumentation requested for the benefit of NIH-funded investigators at UVa. [unreadable] [unreadable]